US 6374147 B1 Abstract An apparatus and method for providing coordinated control of a work implement of a work machine. The implement includes a boom having a first end portion and a second end portion, with the first end portion pivotally connected to the frame and the second end portion pivotally connected to a load-engaging member. The apparatus includes a boom position sensor adapted for providing a boom position signal, and an input device adapted for delivering a desired boom velocity signal indicative of the desired velocity of the boom. The desired velocity of the boom includes a desired angular velocity and a desired linear velocity. The apparatus receives the boom position signal and the desired boom velocity signal, and determines an actual velocity of the boom as a function of the boom position signal. The apparatus also compares the actual velocity of the boom and the desired velocity of the boom, and modifies the desired angular velocity and the desired linear velocity in response to a difference between the desired and actual velocities of the boom.
Claims(35) 1. An apparatus for providing coordinated control of an implement of a work machine having a frame, the implement comprising a boom having a first end portion and a second end portion, with the first end portion pivotally connected to the frame, comprising:
a boom position sensor adapted for delivering a boom position signal;
an input device adapted for delivering a desired boom velocity signal indicative of a desired velocity of the boom, the desired velocity including a desired angular velocity and a desired linear velocity; and
a control system adapted for receiving the boom position signal and the desired boom velocity signal, and determining an actual velocity of the boom, an actual velocity ratio, and a desired velocity ratio, the control system being further adapted for comparing the actual velocity of the boom and the desired velocity of the boom, and modifying the desired angular velocity and the desired linear velocity as a function of said actual and desired velocity ratios in response to a difference between the desired and actual velocities of the boom.
2. An apparatus, as set forth in
a first actuator associated with the boom;
a second actuator associated with the boom; and
wherein the control system is adapted for actuating the first actuator and the second actuator as a function of the desired angular velocity and the desired linear velocity, respectively.
3. An apparatus, as set forth in
4. An apparatus, as set forth in
5. An apparatus, as set forth in
6. An apparatus, as set forth in
7. An apparatus, as set forth in
8. An apparatus, as set forth in
9. An apparatus, as set forth in
wherein the control system is adapted for receiving the boom angle signal and the boom length signal, and responsively determining an actual angular velocity and an actual linear velocity.
10. An apparatus for providing coordinated control of an implement of a work machine having a frame, the implement comprising a boom having a first end portion and a second end portion, with the first end portion pivotally connected to the frame, comprising:
a boom position sensor adapted for delivering a boom position signal, wherein the boom position sensor includes an angle sensor adapted for sensing an angle of the boom relative to the frame, and a length sensor adapted for sensing a length of the boom, wherein the angle sensor and the length sensor are adapted for delivering a boom angle signal and a boom length signal, respectively;
an input device adapted for delivering a desired boom velocity signal indicative of a desired velocity of the boom, the desired velocity including a desired angular velocity and a desired linear velocity; and
a control system adapted for receiving the boom position signal and the desired boom velocity signal, and determining an actual velocity of the boom, the control system being further adapted for comparing the actual velocity of the boom and the desired velocity of the boom, and modifying the desired angular velocity and the desired linear velocity in response to a difference between the desired and actual velocities of the boom,
wherein the control system is adapted for receiving the boom angle signal and the boom length signal, and responsively determining an actual angular velocity and an actual linear velocity,
wherein the control system is adapted for determining an actual angular velocity ratio and an actual linear velocity ratio;
wherein the actual angular velocity ratio is computed by dividing the actual angular velocity by a summation of both an absolute value of the actual angular velocity and an absolute value of the actual linear velocity; and
wherein the actual linear velocity ratio is computed by dividing the actual linear velocity by a summation of both an absolute value of the actual angular velocity and an absolute value of the actual linear velocity.
11. An apparatus, as set forth in
12. An apparatus, as set forth in
wherein the desired angular velocity ratio is computed by dividing the desired angular velocity by a summation of both an absolute value of the desired angular velocity and an absolute value of the desired linear velocity; and
wherein the desired linear velocity ratio is computed by dividing the desired linear velocity by a summation of both an absolute value of the desired angular velocity and an absolute value of the desired linear velocity.
13. An apparatus, as set forth in
14. An apparatus, as set forth in
15. An apparatus, as set forth in
16. An apparatus, as set forth in
wherein the control system is adapted for receiving the inclination signal, and responsively modifying the desired velocity of the boom.
17. An apparatus, as set forth in
18. An apparatus, as set forth in
19. An apparatus, as set forth in
20. An apparatus, as set forth in
21. An apparatus, as set forth in
22. An apparatus, as set forth in
23. An apparatus, as set forth in
24. An apparatus, as set forth in
25. A method for providing coordinated control of an implement of a work machine having a frame, the work implement comprising a boom pivotally connected to the frame, comprising the steps of:
sensing a position of the boom, and responsively delivering a boom position signal;
delivering a desired boom velocity signal indicative of a desired velocity of the boom, the desired velocity including a desired angular velocity and a desired linear velocity;
determining an actual velocity of the boom as a function of the boom position signal;
determining an actual velocity ratio and a desired velocity ratio as a function of said actual velocity and said desired velocity;
comparing the actual velocity of the boom and the desired velocity of the boom; and
modifying the desired angular velocity and the desired linear velocity as a function of said actual velocity and desired velocity ratios in response to a difference between the actual and desired velocities of the boom.
26. A method, as set forth in
27. A method, as set forth in
28. A method, as set forth in
29. A method, as set forth in
sensing both an angle of the boom relative to the frame, and a length of the boom, and responsively delivering a boom angle signal and a boom length signal, respectively; and
receiving the boom angle signal and the boom length signal, and responsively determining an actual angular velocity and an actual linear velocity.
30. A method for providing coordinated control of an implement of a work machine having a frame, the work implement comprising a boom pivotally connected to the frame, comprising the steps of:
sensing both an angle of the boom relative to the frame, and a length of the boom, and responsively delivering a boom angle signal and a boom length signal, respectively;
receiving the boom angle signal and the boom length signal, and responsively determining an actual angular velocity and an actual linear velocity;
delivering a desired boom velocity signal indicative of a desired velocity of the boom, the desired velocity including a desired angular velocity and a desired linear velocity;
determining an actual velocity of the boom as a function of the boom angle signal and a boom length signal;
determining an actual angular velocity ratio and an actual linear velocity ratio;
determining a desired angular velocity ratio and a desired linear velocity ratio;
comparing the actual velocity of the boom and the desired velocity of the boom; and
modifying the desired angular velocity and the desired linear velocity in response to a difference between the actual and desired velocities of the boom.
31. A method, as set forth in
wherein determining the actual linear velocity ratio includes the step of dividing the actual linear velocity by a summation of both an absolute value of the actual angular velocity and an absolute value of the actual linear velocity;
wherein determining the desired angular velocity ratio includes the step of dividing the desired angular velocity by a summation of both an absolute value of the desired angular velocity and an absolute value of the desired linear velocity; and
wherein determining the desired linear velocity ratio includes the step of dividing the desired linear velocity by a summation of both an absolute value of the desired linear velocity and an absolute value of the desired angular velocity.
32. A method, as set forth in
determining an actual velocity ratio as a function of the actual angular velocity ratio and the actual linear velocity ratio; and
determining a desired velocity ratio as a function of the desired angular velocity ratio and the desired linear velocity ratio.
33. A method, as set forth in
34. A method, as set forth in
35. A method for providing coordinated control of an implement of a work machine having a frame, the work implement comprising a boom having a first end portion and a second end portion, with the first end portion pivotally connected to the frame and the second end portion pivotally connected to a load-engaging member, comprising the steps of:
(a) sensing both an angle of the boom relative to the frame, and a length of the boom, and responsively delivering a boom angle signal and a boom length signal, respectively;
(b) receiving the boom angle signal and the boom length signal, and responsively determining an actual angular velocity and an actual linear velocity;
(c) delivering a desired boom velocity signal indicative of a desired velocity of the boom, the desired velocity including a desired angular velocity and a desired linear velocity;
(d) sensing an angle of inclination of the frame relative to a reference plane, and responsively modifying the desired velocity of the boom;
(e) determining an actual angular velocity ratio by dividing the actual angular velocity by a summation of both an absolute value of the actual angular velocity and an absolute value of the actual linear velocity;
(f) determining an actual linear velocity ratio by dividing the actual linear velocity by the summation of both the absolute value of the actual angular velocity and the absolute value of the actual linear velocity;
(g) determining a desired angular velocity ratio by dividing the desired angular velocity by a summation of both an absolute value of the desired angular velocity and an absolute value of the actual linear velocity;
(h) determining a desired linear velocity ratio by dividing the desired linear velocity by the summation of both the absolute value of the desired angular velocity and the absolute value of the desired linear velocity;
(i) determining an actual velocity ratio as a function of the actual angular velocity ratio and the actual linear velocity ratio;
(j) determining a desired velocity ratio as a function of the desired angular velocity ratio and the desired linear velocity ratio;
(k) modifying the desired angular velocity ratio and the desired linear velocity ratio in response to a difference between the desired velocity ratio and the actual velocity ratio; and
(l) actuating a first actuator and a second actuator as a function of the desired velocity ratio.
Description This invention relates generally to an apparatus and method for controlling a work implement of a work machine and, more particularly, to an apparatus and method for providing coordinated control of the work implement in order to produce linear movement of the work implement. Work machines, such excavators, backhoe loaders, wheel loaders, telescopic material handlers, and the like, are adapted for digging, loading, pallet-lifting, etc. These operations usually require the use of two or more manually-operated control levers for controlling the position and orientation of the work implement. As an example, a telescopic material handler includes a telescoping boom having a load-engaging member, e.g., pallet lifting forks, connected at one end of the boom. Two control levers are used to independently actuate hydraulic cylinders adapted for controlling the angle of the boom with respect to a reference plane, and the length of the boom, respectively. Frequently, linear or straight-line movement of the forks are required, e.g., when the forks of the telescopic material handler are to be driven under a pallet in order to lift the pallet. In order to effect such linear movement, the angle of the boom and the length of the boom must be simultaneously controlled. Extensive operator skill is required for coordinating control of the levers while performing these complex operations, thus increasing operator fatigue for skilled operators, and the training time required for lesser skilled operators. The present invention is directed to overcoming one or more of the problems as set forth above. In one aspect of the present invention, an apparatus for providing coordinated control of a work implement of a work machine having a frame is disclosed. The implement includes a boom pivotally connected to the frame. The apparatus includes a boom position sensor adapted for providing a boom position signal, and an input device adapted for delivering a desired boom velocity signal indicative of the desired velocity of the boom. The desired velocity includes a desired angular velocity and a desired linear velocity. The apparatus receives the boom position signal and the desired boom velocity signal, and determines an actual velocity of the boom as a function of the boom position signal. The apparatus further compares the actual velocity of the boom and the desired velocity of the boom, and modifies the desired angular velocity and the desired linear velocity in response to a difference between the desired and actual velocities of the boom. In another aspect of the present invention, a method for providing coordinated control of a work implement of a work machine is disclosed. The method includes the steps of sensing a position of the boom, and responsively delivering a boom position signal. The method also includes the step of delivering a desired boom velocity signal indicative of the desired velocity of the boom, the desired velocity including a desired angular velocity and a desired linear velocity. The method further includes the steps of determining an actual velocity of the boom as a function of the boom position signal, comparing the actual velocity of the boom and the desired velocity of the boom, and modifying the desired angular velocity and the desired linear velocity in response to a difference between the actual and desired velocities of the boom. FIG. 1 is a diagrammatic illustration of a work machine suitable for use with an embodiment of the present invention; FIG. 2 is a block diagram illustrating an embodiment of the present invention; FIG. 3 is a block diagram illustrating an embodiment of a control system of the present invention; FIG. 4 illustrates examples of a plurality of velocity ratio vectors associated with an embodiment of the present invention; and FIG. 5 is a flow diagram illustrating an embodiment of the present invention. With reference to FIGS. 1-5, the present invention provides an apparatus and method for providing coordinated control of a work implement With particular reference to FIG. 1, an illustration of a telescopic material handler The boom The angle of the boom For illustrative purposes, only two actuators With reference to FIG. 2, the first and second actuators In the preferred embodiment, the input device The operator-controlled joystick The control system It can be appreciated by those skilled in the art that other types of sensors and combinations thereof may be included in the boom position sensor The control system In the preferred embodiment, the control system Although the input device Referring now to FIG. 3, a block diagram of the control system Based on the inclination of the machine The adjusted desired velocity requests, represented in Cartesian coordinates, are transformed at control box Boom position signals representing the position and orientation of the boom The desired velocity commands are transformed into a desired velocity ratio at control box It is to be understood that the units for angular velocity and linear velocity in the above equation have been adjusted in order to provide common units. Together, the combined angular velocity ratio and linear velocity ratio represent a velocity ratio vector Preferably, the desired and actual velocity ratios represent the desired and actual velocities of the first actuator The desired velocity ratio is compared to the actual velocity ratio at control box As an example, a desired velocity ratio comprising a desired angular velocity ratio of 60% and a desired linear velocity ratio of 40% is requested by the input device The desired angular velocity and the desired linear velocity ratios are converted to desired flows to the respective actuators in a velocity to flow transform control box The desired flows are scaled in control box With reference to FIG. 5, a flow diagram is shown illustrating the operation of an embodiment of the present invention. In a first control box In a second control box Control then proceeds to a third control box In a fifth control box Control then proceeds to a sixth control block The actual velocity ratio is compared to the desired velocity ratio, and the desired velocity ratio, i.e., the desired angular velocity and the desired linear velocity, is responsively modified in the seventh control block In an eighth control block As one example of an application of the present invention, telescopic material handlers are used generally for loading various types of material. In such applications, linear movement of the boom is often required. For example, when the forks of the telescopic material handler are to be driven under a pallet in order to lift the pallet, linear movement of the fork in the horizontal plane is required. Similarly, when the pallet is to be lifted in the vertical direction, linear movement of the fork in the vertical plane is required. In both situations, the length and angle of the boom must be simultaneously coordinated to effect such movement. The control system of the present invention receives a desired velocity request from an operator via an input device, e.g., a joystick. The desired velocity includes a desired angular velocity of the boom, and a desired linear velocity of the boom. The desired angular velocity and the desired linear velocity represents the desired velocities of the respective hydraulic cylinders. The desired velocities are converted to desired flows to the respective cylinders. However, in some situations, one or more of the cylinders does not receive the desired flow due to the increased demand of another cylinder. As a result, the cylinders do not operate in proportion to operator demand. Operators frequently experience fatigue attempting to avoid or overcome such situations. The control system of the present invention attempts to eliminate problems of this type, by calculating a compensating error as a function of a comparison between the actual velocity of the boom, and the desired velocity of the boom. This compensating error is used to modify the desired angular velocity and the desired linear velocity, which in turn are used to simultaneously coordinate the flow to the respective hydraulic cylinders to provide linear movement of the fork, thus reducing operator fatigue and improving efficiency. Other aspects, objects, and features of the present invention can be obtained from a study of the drawings, the disclosure, and the appended claims. Patent Citations
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